CN115397557A

CN115397557A - Pipette tip

Info

Publication number: CN115397557A
Application number: CN202180025758.9A
Authority: CN
Inventors: H·雷特维施; M·莱昂哈德特; L·科赫
Original assignee: Epedov Europe Ag
Current assignee: Epedov Europe Ag
Priority date: 2020-04-03
Filing date: 2021-03-26
Publication date: 2022-11-25
Also published as: EP4100164A1; US20230138840A1; WO2021198086A1; EP3888791A1; JP2023520982A

Abstract

The invention relates to a pipette tip made of plastic, having an elongate tubular body which has a lower opening at a lower end for the passage of liquid and an upper opening at an upper end for clamping onto a spigot portion of a pipetting device, wherein a fitting region for the spigot portion is present on an inner circumference of the tubular body beside the upper opening, wherein at least one flattened section extending in the axial direction is present on an outer circumference of the tubular body beside the upper opening, wherein the wall thickness of the tubular body in a cross section of the tubular body decreases in the flattened section in the direction of a central region of the flattened section from one of two regions of the tubular body adjoining the flattened section, and the flattened section has a straight profile or a curved profile with a smaller curvature than the adjoining region in the cross section of the tubular body.

Description

Pipette tip

Technical Field

The present invention relates to pipette tips.

Background

Pipette tips are used in conjunction with pipettes and other metering devices, in particular in medical, biological, biochemical and chemical laboratories for metering liquids. Hereinafter, pipettes and other metering devices are generically referred to as "pipetting devices". A pipette tip has an elongated, tubular body with a lower opening at a lower end for passing liquid and an upper opening at an upper end for clamping onto a spigot portion of a pipetting device. Pipette tips are often of a generally conical shape with a cross-section that increases from a lower opening to an upper opening. Standardized cone-shaped or truncated cone-shaped sockets (working cones) are known with standard geometries which are used uniformly by many manufacturers and which are characterized for each pipette tip size by a specific average diameter of the cone-shaped socket and a specific cone angle.

Multi-channel pipetting devices are used to simultaneously receive liquid from one or more vessels or to discharge liquid into one or more vessels. The multichannel pipetting devices are frequently used for processing microtiter plates having a large number of containers in a matrix arrangement. For this purpose, the multi-channel pipetting device has a plurality of conical sleeve sections arranged parallel next to one another in one or more parallel rows, onto which sleeve sections pipette tips can be clamped. In order to adapt to the frequently used format of microtiter plates with 96 (8 x 12) or 384 (16 x 24) containers (cuvettes) according to the ANSI standard, multichannel pipettors with 8, 12, 16 or 24 sleeve portions in one row are known. Also known are multi-channel metering devices having a metering head with 96 or 384 pockets. Adjacent sockets have a spacing of 9mm or 4.5mm from one another, corresponding to the spacing of adjacent vessels of a microtiter plate having 96 or 384 vessels.

In the embodiment as an air cushion pipetting device, the pipetting device has at least one displacement device for air, which is connected in communication with the through-opening of the at least one cuff portion. By means of the displacement device, the air cushion can be displaced in order to suck in and discharge liquid from a pipette tip clamped onto the collar. The displacement device is mostly designed as a cylinder with a piston movable therein. Displacement devices having a displacement chamber and having at least one deformable wall are also known, wherein the deformation of the wall causes displacement of an air cushion.

In the embodiment of the pipetting device as a direct displacer, a small piston is provided in the pipette tip, which piston is coupled to a coupling element of a piston drive of the pipetting device when the pipette tip is inserted onto the socket, which coupling element can be displaced in a through-hole of the socket.

The accommodation of liquid into the pipette tip is preferably carried out in a single step or in a plurality of substeps. The discharge of the liquid takes place in a single step during pipetting and in a plurality of small steps during dispensing.

Pipetting devices usually have a detacher which acts on the upper edge of the pipette tip in order to press it off the collar. In a multi-channel pipetting device, the detacher can be pressed simultaneously against the upper edges of a plurality of pipette tips. By means of the detacher, the user can detach a liquid-contaminated pipette tip from the socket portion without touching the pipette tip.

The pipetting device may be a hand-held pipette that a user can hold and manipulate with only one hand. The pipetting device can also be a metering table ("pipetting table") or a metering robot ("pipetting robot") in which the metering head can be displaced together with one or more pocket sections over a work surface at a robot arm or at another transfer system. The pipetting device can also be a component of a laboratory automation ("workstation") which, in addition to metering, can carry out further treatments of the liquid (e.g. mixing, temperature regulation, analysis).

To avoid incorrect metering, the pipette tip must be clamped onto the socket in a sufficiently fixed or sealed manner. Furthermore, the forces for inserting and removing pipette tips from the pocket are not allowed to be too high. Conventional pipette tips are thick-walled and hard in the contact area with the conical collar. During insertion, the pipette tip is widened elastically over the circumference by the collar. The elastic characteristic line is steep, so that a high insertion force can be applied. After the insertion of the sleeve, a correspondingly high static friction acts between the sleeve mouth and the pipette tip, which must be overcome during the detachment. The user is loaded with high forces for plugging and detaching the pipette tip. Disease may thereby be caused, which disease is summarized under the term "cumulative trauma disease" (CTD). If the plugging and the disconnection are carried out by means of a motor drive, this needs to be correspondingly efficient and have a high current consumption.

US6197259 describes a pipette tip which can be fixedly inserted onto a spigot portion of a pipette by using a relatively small axial insertion force of six pounds (26.7N) and which can be detached therefrom by using a relatively small detachment force of three pounds (13.3N). A pipette tip has a conical upper end with an inner diameter at the upper end which is greater than the diameter of a spigot of a pipette onto which the pipette tip can be plugged. Furthermore, the pipette tip has a hollow middle section and has an annular sealing region at the connection between the upper end and the middle section. The middle section has a side wall on and beside the sealing area, the side wall having a wall thickness of between 0.2mm and 0.5 mm. The annular sealing region has an inner diameter smaller than the value "x" and is designed such that it engages with the lower end of the sealing region of the cuff portion so as to be radially widened when the cuff portion is introduced. As a result, a liquid-tight seal is produced between the sealing region of the collar and the sealing region of the pipette tip. Furthermore, the pipette tip has lateral stabilizing means on the inner side next to the sealing region, which engage with the outer surface of the collar in order to stabilize the pipette tip on the collar. The lateral stabilizing means has at least three contacts spaced apart from each other in the circumferential direction, said contacts extending inwardly from the inner surface of the pipette tip. The contact portions are diametrically spaced apart such that they readily engage and slide past the lower end of the collar portion without widening the side wall of the pipette tip on which the contact portions are provided. When the lower end of the sealing region of the collar portion engages with the sealing region of the pipette tip, the pipette tip extends in and directly beside the sealing region. When the contact portion guides the pipette tip over the pocket portion, the side wall of the pipette tip is deformed inwardly between the contact portions and is not widened, whereby the force to be applied in order to press into the pocket portion is kept small. The spigot portion can be pressed deeper into the pipette tip with increasing plunging force. Correspondingly, a high detachment force can be applied for detaching the pipette tip from the pocket. Such a configuration is only suitable for relatively large pipette tips, based on the inwardly projecting contact portions.

US6568288 describes a pipette tip having an annular sealing region and a substantially cylindrical lateral guide region which are axially spaced apart from one another, wherein the sealing region is sufficiently thin to form a press fit and an air-tight seal between a sealing surface of the sealing region and the sealing region when the annular sealing region and the cylindrical lateral guide region which are axially spaced apart from one another are pressed into a collar of a pipette. The wall thickness in the sealing region is preferably between 0.2mm and 0.5 mm. The sealing surface is outside the annular, radially outwardly projecting projection adjacent the lower end of the cuff. The pipette tip has a circular, upwardly turned and inwardly directed shoulder on the inner circumference for the purpose of limiting the spigot to the pocket. The force for the insert should be approximately two pounds (8.9N) and the force for disengagement should be approximately one pound (4.45N). With depth stops, incomplete immersion may occur when a plurality of pipette tips are received simultaneously from a tray or rack by means of a multichannel pipetting device. When the tray or rack tends to bend downward between the lateral edges, the nesting of the two outer pockets on the shoulders of the two outer pipette tips may result in the additional pockets not sinking sufficiently into the pipette tip disposed therebetween.

US 696004B 2 describes a pipette tip having an annular sealing area with an inner sealing surface on a side wall which is sufficiently thin in the sealing area to expand slightly and form a press fit and air tight seal between the sealing surface and the sealing area of a collar of a pipette which is embedded in the pipette tip. The pipette tip has an annular, inwardly and upwardly directed shoulder which limits the insertion of the spigot portion. The cuff portion includes two cylindrical sections having different diameters. The annular sealing region of the socket encloses the sealing edge at the connecting portion of the lower end of the cylindrical section of the socket and at the outermost edge of the radially extending transition. Preferably, the force for engaging and disengaging a pipette tip is less than two pounds (8.9N). A depth stop may lead to an insufficient penetration of the collar when a plurality of pipette tips are accommodated simultaneously by means of a multi-channel pipetting device.

EP2138234A1 describes a pipette tip which, for the detachable connection to a collar of a pipetting device, has a flexible tubular connecting section at the upper end of an elongated tubular section, said connecting section having a profile which is wavy in cross section and which increases the stretchability of the fitting region. The mating region is reversibly extendable by more than 20% when inserted onto the socket portion. For a sealing fit, the wavy contour needs to be drawn smoothly over the sleeve portion, whereby the further stretchability is only small. Therefore, precise manufacturing of pipette tips is required. Furthermore, between the fitting region and the tubular region there is a shoulder projecting radially inward, which produces a depth stop for the socket portion, which can lead to an insufficient penetration of the socket portion when accommodating a pipette tip by means of a multichannel pipetting device.

EP2606977A1 describes a pipette tip in the form of an elongated small tube having a lower opening at a lower end for the passage of liquid and an upper opening at an upper end, wherein a fitting region for insertion onto a standardized, conical sleeve portion of a pipetting device is present on an inner circumference next to the upper opening. The fitting region has a retaining region with a radially inwardly projecting, axially extending rib and, below the retaining region, a sealing region with a circumferentially encircling, inwardly projecting sealing projection. The fitting region is configured such that, when the pipette tip is plugged onto the collar portion with a plugging force that ensures the retention and sealing of the pipette tip on the collar portion, the rib is partially plastically deformed and an elastic deformation occurs outside the rib in the fitting region. Below the sealing region, the pipette tip has a stop region which widens conically towards the upper opening for the purpose of limiting the insert. This ensures a reliable seal at the mouthpiece of the pipetting device and the detachment force to be applied for detachment is significantly reduced. The structure is particularly suitable for relatively large pipette tips having nominal volumes of 2.5mL, 5.0mL and 10 mL. For smaller pipette tips, their difficult manufacture based on fine ribs is not well suited.

EP3115110A1 describes a pipette tip having a tubular body and a fitting region for insertion onto a conical sleeve mouth of a pipetting device, said fitting region having a circumferential, inwardly projecting sealing projection on the inner circumference at a distance from the upper opening, a circumferential, downwardly tapering detent region below the sealing projection and tapering more strongly downward than the sleeve mouth, and a circumferential, inwardly projecting support projection above the sealing projection. The sealing projection can be clamped in a sealing manner onto the sleeve opening under elastic deformation, wherein the braking region further bears against the sleeve opening at the bottom, and the support projection further bears against the sleeve opening at the top without pretension or is spaced apart from the sleeve opening by a surrounding gap. Pipette tips are well-sealed and can be reliably clamped to the orifice of a pipetting device, can be detached from the orifice with reduced effort and are also well-suited for smaller pipette tip sizes. The high force consumption during clamping onto the cuff and during detachment from the cuff is disadvantageous.

WO2011/091308A2 describes a pipette tip having a circular ring-shaped flange at the proximal end of the proximal section and axially directed ribs in the proximal section, which ribs are spaced apart from one another in the circumferential direction. The flange should increase the rigidity of the pipette tip and simplify the alignment of the dispenser with the pipette tip. The ribs should limit the axial expandability of the pipette tip in the proximal region. Pipette tips with filling volumes of 200. Mu.l and 1000. Mu.l have a plunging force of over 1000g (10N) and up to 2000g (20N) on five different pipettes.

From US7335337B1, an ergonomically optimized pipette tip is known, which can be reliably secured to a pipette in an operable manner, wherein the insertion and removal forces are reduced. Pipette tips have elastic expansion elements, by means of which axial insertion and detachment forces can be reduced. The elastic expansion element is arranged in the upper section of the pipette tip above a sealing ring which surrounds the inner circumference. They are formed by outwardly arched regions of reduced wall thickness between the cylindrical or conical sections of the pipette tip. When the collar of the pipette is inserted into the upper opening of the pipette tip, the expansion element is flattened and the segmented wall segment widens. The pipette tip is guided and aligned on the collar portion by means of ribs on the inner side of the wall section. However, the insertion force is still high, since the pipette tips have a large wall thickness in the region of the surrounding sealing ring and can only stretch slightly and increase strongly when the expansion element is flattened out.

WO2018/213196A1 describes a pipette tip having a proximal section with longitudinally directed grooves and panels alternating with each other, the grooves and panels being configured to facilitate widening and compression of the wall when the pipette tip is placed in and sealingly engaged with a correspondingly configured drain. By these measures, the axial forces for clamping the pipette tip to the drain and for releasing the pipette tip from the drain for liquid are reduced. The grooves are configured in a stepped, V-shaped or U-shaped manner. A plurality of grooves and panels are alternately arranged on the circumference of the proximal section. In order to form the groove, the constriction and the substantially right-angled corner between the groove and the panel in the injection-molding tool must be filled with the plasticized plastic mass during injection molding. Thereby limiting throughput and reducing the dimensional stability and strength of the pipette tip. There is also the following risk: when the pipette tip is clamped on the collar, it tears at the bottom of the groove and does not fit sealingly on the collar. Furthermore, due to the strong structuring of the proximal section of the pipette tip, it is difficult to apply a marking to the pipette tip.

Disclosure of Invention

Starting from this, the object of the present invention is to provide a pipette tip which can be clamped sufficiently firmly and sealingly onto the spigot of the pipette tip with reduced insertion and detachment forces, has more favorable manufacturing properties, at the same time has improved dimensional stability and strength, and is better suited for the provision of markings for different pipette tips.

This object is achieved by a pipette tip having the features of claim 1. Advantageous embodiments of the pipette tip are given in the dependent claims.

A plastic pipette tip according to the invention comprises an elongated tubular body which has a lower opening at the lower end of the tubular body for the passage of liquid and an upper opening at the upper end of the tubular body for clamping onto a spigot of a pipetting device, wherein a fitting region for the spigot is present on the inner circumference of the tubular body beside the upper opening, characterized in that at least one flattened section extending in the axial direction is present on the outer circumference of the tubular body beside the upper opening, the wall thickness of the tubular body in the cross section of the tubular body in each case decreases from one of the two regions of the tubular body adjoining the flattened section in the flattened section towards the central region of the flattened section, and the flattened section has in the cross section of the tubular body (i) a straight-line contour or (ii) a curved contour which is less curved than the adjoining region.

The pipette tip according to the invention has a smaller wall thickness in the region of the flattened section than on both side edges of the flattened section and, if applicable, in the region of the tubular body adjoining the flattened section. The deformability of the pipette tip when it is clamped onto the collar of the pipetting device is thereby improved, so that a reliable sealing of the pipette tip on the collar can be achieved even with relatively low insertion forces. The pipette tip can be designed such that it is only elastically deformed when it is clamped with a specific force onto a defined socket of the pipetting device. However, the pipette tip can also be designed such that it is plastically deformed when it is clamped with a specific force onto a defined socket of the pipetting device. In the case of elastic deformation, the socket force increases in proportion to the deformation. The elastic deformation may be fully recovered after the pipette tip is loosened from the pocket. When the elastic limit is exceeded, plastic deformation occurs. Plastic deformation is an irreversible deformation that does not recover itself after the pipette tip is loosened from the cuff. In the case of plastic deformation, the socket force no longer increases or only slightly increases with the deformation. Elastic or plastic deformation preferably occurs in the region of the flattened section, since the pipette tip has a minimum wall thickness in the region of the flattened section next to the upper opening. The force required for the sealed clamping of the pipette tip to the socket can thereby be kept low. In the case of plastic deformation, the insertion force can be limited to a predetermined limit value.

For the production by injection molding, it is advantageous that the plastic mass can fill the cavity in the injection molding tool better in the region of the flattened section than in the region of the groove in conventional pipette tips due to the lower pressure loss at the flattened section. Thereby, also the joint seams may be reduced, and a more dimensionally stable and robust pipette tip may be achieved. The increased strength prevents the pipette tip from tearing at the point of minimal wall thickness due to the insertion force.

Another advantage resides in: the flattening portion may be used to set a logo for a pipette tip. In particular, descriptive information about the pipette tip and/or its manufacture, for example about the pipette tip size, the material or purity of the pipette tip, the manufacturer, the brand and/or the production mold used for the manufacture, can be placed on the flattening during the injection molding. The pipette tip size is the maximum volume with which it can be dosed. Pipette tips that differ from each other in respect of at least one of the above criteria are also referred to in this application as "pipette tips of different pipette tip types". The marking can be produced in the form of raised or recessed letters, numbers, signs or symbols during injection molding or can also be printed later on. Furthermore, recognition by a user setting, for example by stamping, writing with a writing instrument or affixing a label, may be considered. Furthermore, the flattened portion itself may be used as an identification feature to distinguish between different pipette tip types.

The flattened section may also serve as an anti-roll protection to prevent pipette tips placed on a work surface or other surface from rolling away.

The flattening may have a rectilinear profile and/or an outwardly (convex) and/or inwardly (concave) curved profile in the cross-section of the tubular body. According to a preferred embodiment, the profile of the flattened section is substantially or only rectilinear, or substantially or only outwardly curved, or substantially or only inwardly curved. According to one embodiment of the invention, the radius of curvature is constant along the respective profile. According to another embodiment, the radius of curvature varies along each profile or part thereof. According to another embodiment, the profile of the flattening is straight in the subsections and is curved identically or differently in the subsections. For example, the profile of the flattened portion is curved outwardly or straight at two edges and curved outwardly or inwardly therebetween such that the profile of the flattened portion approximates a generally V-shape. According to another embodiment, the profile of the flattened section is curved differently in the partial sections. The different curvatures may be curvatures having different radii of curvature or outward and inward curvatures having the same or different radii of curvature.

If the profile of the flattened portion is curved, the curvature is less than the curvature of the region of the tubular body adjacent the flattened portion. The curvature represents the inverse of the radius of curvature of the corresponding profile. In the case of an outwardly curved profile, the flattened section is obtained by the curvature of the flattened section being smaller than the curvature of the region of the tubular body adjoining the flattened section. In the case of an inwardly curved profile, the flattened section is also obtained in that the curvature of the flattened section is smaller than the curvature of the region of the tubular body adjoining the flattened section. The flattened portion is particularly suitable for providing a marker for a pipette tip, since the curvature is smaller than the curvature of the region of the tubular body adjoining the flattened portion.

According to one embodiment of the invention, the tubular body has, in a cross section at the outer circumference, a contour in the shape of a circular arc at least in a region adjoining the flattened section, and the flattened section has a contour in the shape of a straight line or a contour in the shape of a circular arc with a larger radius of curvature than the region adjoining the flattened section. According to a preferred embodiment, the area adjoining the flattening is generally circular-arc-shaped. However, the invention also relates to embodiments in which the contour of the region adjoining the flattening deviates from a circular arc shape, for example with an oval or otherwise curved course. Furthermore, the profile of the flattened section may deviate from a straight or circular arc-shaped curved course, for example the profile of the flattened section may have an oval or otherwise curved course.

According to another embodiment, the tubular body has a rectilinear profile and/or a curved profile in the flattened section in all cross sections of the at least one flattened section. According to a preferred embodiment, the tubular body has only a straight profile in the flattened section in all cross sections of the flattened section, or only a curved profile in the flattened section in all cross sections of the flattened section. According to another embodiment, the tubular body has in all cross sections of the flattened section only profiles curved with the same radius of curvature in the flattened section, or profiles curved with different radii of curvature in different cross sections, wherein the curvature of the profiles preferably changes gradually from one cross section to the next. According to another embodiment, the flattening has an outwardly curved profile and an inwardly curved profile in different cross sections, wherein the curvature of the profiles preferably changes gradually from one cross section to the next.

According to another embodiment, the flattening has an inwardly curved profile. For example, the inwardly curved contour is a contour which is curved inwardly overall with the same or different curvature or a contour which is curved inwardly in the central region, i.e. a contour which is straight at the two side edges, which is generally approximately V-shaped. Preferably, the inwardly curved flattened section is circumferentially in the range of more than 10 °, preferably more than 30 °. Preferably, at least 3 of the flattenings with the inwardly curved profiles are evenly distributed over the circumference and have the same width or a wider width than the area between the flattenings with the inwardly curved profiles.

According to another embodiment, the at least one flattened portion extends upwardly to a spaced distance from the upper end of the tubular body. In this way, an upper edge surrounding with a uniform wall thickness can be realized at the upper end of the pipette tip, which is advantageous for detaching the pipette tip from the collar by means of a detachment device of the pipetting device. According to another embodiment, the upper edge of the pipette tip is a circumferential flange. The flange may be used to retain a pipette tip in a hole of a holder (rack) for the pipette tip.

According to another embodiment, the flattened portion extends up to the upper end of the tubular body. Extending the flattened portion to the upper end portion facilitates deformation of the pipette tip with reduced force consumption.

According to another embodiment, the tubular body has a shoulder on the outer circumference. The shoulder can be used to support a pipette tip in a bore of a holder for the pipette tip. According to another embodiment, the flattened portion extends downwardly at least as far as or beyond the shoulder.

According to another embodiment, the tubular body has a plurality of, preferably three, flattened portions on the outer circumference. By means of a plurality of flattening sections, the effort required for deforming the pipette tip can be further reduced. Furthermore, different pipette tip types may be characterized differently by pipette tips having different numbers and/or positions and/or sizes of flattened portions.

According to another embodiment, the flattened portions are evenly distributed over the outer circumference of the tubular body. Thereby, the uniform widening of the pipette tip can be achieved. However, the flattening may also be distributed unevenly over the outer circumference of the tubular body, in particular in order to characterize different pipette tip types differently.

Pipette tips according to the invention comprise in particular the following examples:

if the pipette tip has at least one flattened section which, according to feature (i), has a linear contour in the cross section of the tubular body, the pipette tip can have a single flattened section and a single curved adjoining region which extends from one side edge of the flattened section to the other side edge of the flattened section. Furthermore, the pipette tip may have a plurality of flattened sections with a rectilinear profile in a cross section of the tubular body, which are distributed over the circumference of the tubular body, wherein a curved region adjoins a side edge of a flattened section, which extends up to a side edge of an adjacent flattened section. Furthermore, a pipette tip is provided, which has a plurality of flattenings having a rectilinear contour in the cross-section of the tubular body, wherein the flattenings adjoin one another at side edges such that they overall define a polygon with rectilinear edges in the cross-section of the tubular body.

If the pipette tip has at least one flattened section which, according to feature (ii), has a curved contour in the cross section of the tubular body which is less curved than the region adjoining the flattened section, the pipette tip can have one single flattened section and one single curved adjoining region which extends from one side edge of the flattened section as far as the other side edge of the flattened section. Furthermore, the pipette tip may have a plurality of flattened sections with a curved contour in a cross section of the tubular body, which are distributed over the circumference of the tubular body, wherein a curved region adjoins a side edge of a flattened section, which extends up to a side edge of an adjacent flattened section. The plurality of flattened portions may all be curved in the same manner or in different manners. In particular, the plurality of flattened portions can all be curved outwardly or inwardly or both with the same or different curvatures.

According to another embodiment, the at least one flattening extends parallel to the central axis of the tubular body or extends helically around the central axis of the tubular body. For example, in the case of a helical extension, each flattened portion extends over only a portion of the circumference of the tubular body or extends around the circumference of the tubular body once or more than once.

According to another embodiment, the flattening occupies a greater part of the outer circumference of the tubular body as a whole than the part of the tubular body occupied as a whole by the region adjoining the flattening in the circumferential direction. This can further reduce the effort required for widening the pipette tip.

According to another embodiment, the mating region is conical and/or cylindrical.

According to a further embodiment, the tubular body has at least one inwardly projecting circumferentially surrounding sealing structure and/or at least one inwardly projecting circumferentially surrounding guiding structure or having a plurality of mutually spaced apart segments and/or at least one inwardly projecting circumferentially surrounding braking structure or having a plurality of mutually spaced apart segments on the inner circumference of the mating region. According to a further embodiment, the sealing structure is a sealing bead and/or the guide structure is a guide bead and/or a guide rib and/or a bead-like or nubbed guide projection and/or the detent structure is a detent bead and/or a conical detent region.

The sealing structure produces an annular bearing between the orifice portion of the pipetting device and the pipette tip and thus leads to a good seal with low friction when the pipette tip is inserted onto the orifice portion. Instead of an inwardly projecting sealing structure, the mating region can have a face seal, which is formed, for example, by a conical face or a cylindrical face or a partial section conical and partial section cylindrical face.

The guide structure produces an annular support or a plurality of annular arc-shaped supports spaced apart from one another in the circumferential direction and/or a plurality of approximately point-shaped supports spaced apart from one another in the circumferential direction between the collar section of the pipetting device and the pipette tip and thus leads to good guidance with low friction when the pipette tip is plugged onto the collar section. Even if a force is introduced into the lower end of the pipette tip from one side during wall discharge (liquid discharge on the container wall), the pipette tip is held stably on the spigot by the guide structure.

The braking structure generates an annular or annular-arc-shaped or ramp-shaped bearing between the collar and the pipette tip and brakes the insertion movement of the collar into the pipette tip. The braking effect is determined by the geometry of the braking structure and the cuff and the material properties (in particular the elasticity and roughness) of the pipette tip and the cuff.

According to another embodiment, the guiding structure is arranged above the sealing structure and/or the braking structure is arranged below the sealing structure. According to another embodiment, the guiding structure coincides with the sealing structure and/or the sealing structure coincides with the braking structure. For this purpose, the guide ridge can be designed at the same time as the sealing ridge and/or the sealing ridge can be designed at the same time as the friction ridge.

According to another embodiment, the tubular body has a plurality of sealing and/or guiding and/or braking structures on the inner circumference, which have an undulating contour in a longitudinal section of the tubular body.

According to another embodiment, the tubular body has a widening at the upper opening and/or an introduction slope. The introduction of the orifice of the pipetting device into the pipette tip is facilitated by the widened section and/or the introduction ramp.

According to another embodiment, the pipette tip consists only of a tubular body. According to another embodiment, the pipette tip is an air-cushion pipette tip, i.e. a pipette tip configured for use with an air-cushion pipetting device. According to another embodiment, the air cushion pipette tip consists of only a tubular body.

According to another embodiment, a pipette tip is comprised of a tubular body and of another member. Said further member is for example a small piston which is arranged inside the tubular body and which can be displaced therein. This is a direct displacement pipette tip, i.e. a pipette tip that can be used with a direct displacement pipette pipetting device.

According to another embodiment, the pipette tip is made of at least one thermoplastic, preferably at least one polyolefin, preferably at least one polypropylene and/or ethylene.

According to another embodiment, a pipette tip has one or more of the following features:

-the wall thickness of the tubular body in the circumferential direction alongside the at least one flattened portion falls in the range 0.3mm to 1mm;

the engagement region is internally tapered with a diameter which decreases downwards, wherein the taper angle of the engagement region is selected from the range of 1 ° to 6 °, preferably 1.5 ° to 2.5 °;

the fitting region is designed for insertion onto the socket portion, wherein the cone angle of the conical socket portion or of the conical section of the socket portion is selected from the range from 1.0 ° to 10 °, preferably from 1.3 ° to 7 °, more preferably from 1.5 ° to 3 °;

the sealing and/or guiding and/or braking structures are distributed over the mating region in the longitudinal direction of the tubular body;

the wall thickness of the tubular body is at most 0.3mm at the thinnest point in the region of the flattened section (outside the sealing and/or guiding and/or braking structure);

the wall thickness of the tubular body is at least 0.1mm at the thinnest point in the region of the flattened section (outside the sealing and/or guiding and/or braking structure);

the flattened portion extends in the longitudinal direction of the tubular body over a length of at least 4 mm;

the flattening extends in the longitudinal direction of the tubular body at least over two sealing and/or guiding and/or braking structures.

The present invention further relates to a pipette tip system comprising a plurality of pipette tips according to one of claims 1 to 16 or one of the above-described embodiments, the pipette tips of different pipette tip types having differently configured flats and/or having different markings on the flats.

Furthermore, the invention relates to a pipetting system comprising at least one pipette tip according to one of claims 1 to 16 or one of the above-described embodiments and comprising a single channel pipetting device with a single pocket portion for sheathing one pipette tip and/or a multi-channel pipetting device with a plurality of pocket portions for simultaneously sheathing a plurality of pipette tips.

In the present application, the descriptions "vertical" and "horizontal", "above" and "below" and the descriptions derived therefrom, such as "above" and "below", relate to the arrangement of the pipette tip together with the vertically oriented central axis of the tubular body, with the upper opening above and the lower opening below.

In the present application, each cross-section through the tubular body is a plane oriented perpendicular to the central axis of the tubular body. Each longitudinal section of the tubular body is a plane in which the central axis of the tubular body extends.

Further, the central region of the flattened portion represents a line or strip-shaped area extending between the two side edges of the flattened portion, which may be spaced at the same pitch as the two side edges of the flattened portion or may be spaced at a different pitch from the two side edges of the flattened portion.

Drawings

The invention is explained in more detail below with the aid of drawings of embodiments. In the drawings:

fig. 1 shows a pipette tip in a perspective view from one side;

fig. 2 shows the same pipette tip in a reduced side view;

fig. 3 shows the same pipette tip in cross-section of the mating area;

fig. 4 shows the same pipette tip in enlarged partial cross-section of the mating area;

fig. 5 shows the same pipette tip in a reduced partial section of the fitting area, with an inserted collar of the pipetting device;

fig. 6 shows another pipette tip in perspective view from one side;

fig. 7 shows the same pipette tip in an enlarged side view;

fig. 8 shows the same pipette tip in cross-section of the mating area;

fig. 9 shows the same pipette tip in enlarged partial cross-section of the mating area;

fig. 10 shows the same pipette tip in enlarged partial section of the fitting region with an inserted pocket with a pipetting device.

Detailed Description

In the following explanation of the different embodiments, structures and components denoted with the same reference numerals are provided with the same reference numerals.

According to fig. 1 to 4, a pipette tip 1 has an elongated tubular body 2 with a lower opening 4 at a lower end 3 and an upper opening 6 at an upper end 5. The lower opening 4 is smaller than the upper opening 6.

Generally, the inner and outer diameters of the tubular body 2 increase from the lower opening 4 towards the upper opening 6. The tubular body 2 comprises at the lower part a conical starting section 7, above which a middle section 8 with a smaller cone angle than the starting section 7 and above which a cylindrical head section 9 with a larger dimension than the middle section 8 are comprised. Adjacent to the intermediate section 8, at the outer circumference of the tubular body 2 at the lower side of the head section 9, a downwardly directed outer shoulder 10 is surrounded.

At the outer circumference 11 of the head section there is a flattening 12 extending in the axial direction. In this example, there are three flattened portions 12. The flattening 12 starts at a small distance from the upper end 5 of the tubular body 2 and extends down over the head section 9 until slightly beyond the shoulder 10 into the upper region of the intermediate section 8. The flattened portion 12 is oriented parallel to the central axis of the tubular body 2. The flattened portions 12 are evenly distributed around the outer circumference 11 of the tubular body. In this example, the widths of the flattened section 12 and the region 13 adjoining thereto are approximately the same, respectively.

The tubular body 2 has, in each cross section through the flattened section 12 on the outer circumference 11, a circular-arc-shaped curved contour 14 in the region 13 adjoining the flattened section 12 and a straight contour 15 in the flattened section 12. The circular-arc-shaped contour 14 extends over the entire spacing between two adjacent flattened sections 12, i.e. between the flattened sections 12, the contour 14 is circular-arc-shaped throughout. This is shown in particular in fig. 3.

Above the flattened section 12, the tubular body 2 has a circumferential edge 16 with a uniform wall thickness.

At the upper end, the tubular body 2 has a widened portion 18 at the inner circumference 17, which has an introduction slope 19. This is shown in particular in fig. 4.

Next to the upper opening 6, the tubular body 2 has on the inner circumference 17 a substantially conical or cylindrical fitting region 20 for a conical or cylindrical socket 21 of a pipetting device. The engagement region 20 extends into the head section 9 and is conical, with a cone angle of, for example, 2 ° to 6 °.

The tubular body 2 has, at the inner circumference 17 in the fitting region 20, a plurality of sealing means 22 in the form of inwardly projecting, closed-loop sealing ridges 23 which are spaced apart from one another in the axial direction. Furthermore, the tubular body 2 has, at a small distance from the upper opening 6, inwardly projecting, closed-loop guide structures 24 in the form of guide ridges 25 spaced apart from one another. In general, the tubular body 2 has an undulating sealing and guiding structure 22, 24 in longitudinal section in the fitting region 20.

Below the sealing structure 22, a conical detent region 26 is present at the inner circumference of the head section 9.

At the lower end of the head section 9, the inner contour of the tubular body 2 smoothly transitions into a downwardly tapering middle section 8, which further transitions down into the start section 7.

According to fig. 3, the tubular body 2 has a constant wall thickness throughout the adjoining regions 13 between the flattened sections 12 in cross section.

Furthermore, the wall thickness of the tubular body 2 in the flattened region 12 decreases in each case from the region 13 adjoining the flattened region toward the central region 27 of the flattened region 12.

According to fig. 1 and 2, the flattening 12 is provided with a marking 28. The markings are characters 29 in the form of raised or recessed numbers and letters which are produced during injection molding of the pipette tip 1. The character 29 indicates the pipette tip size and the set of information of the injection molding die in which the pipette tip 1 is injection molded.

For clamping onto the socket 21 of the pipetting device, one or more pipette tips 1 can be held ready in the bore of the holder for pipette tips which are supported with the shoulder 10 on the edge of the bore. According to fig. 5, the socket 21 of the pipetting device can be easily introduced into the pipette tip 1 through the widened section 18 with the introduction slope 19 at the upper opening 6. In the pipette tip, it is guided with little friction by the guide structure 24 and the sealing structure 22. When clamped onto the socket portion 21, the pipette tip 1 can be elastically and/or plastically deformed in the region of the flattened section 12, so that the insertion force is reduced and a reliable sealing of the socket portion 21 on the sealing structure 22 is achieved with a relatively low insertion force.

After pipetting the liquid, the pipette tip 1 can be easily detached from the pocket portion 21 because the detachment force for detachment is also reduced. For detachment, the detachment sleeve of the pipetting device guided over the collar 21 is pressed against the circumferential edge 16 at the upper end 5 of the pipette tip 1 and detaches the pipette tip from the collar 21.

The pipette tip 1 of fig. 6 to 10 is preferably designed for smaller filling volumes than the pipette tip 1 of fig. 1 to 5. Pipette tip 1 differs from the above-described pipette tips in particular by: the elongated tubular body 2 has, above the conical starting section 7, a plurality of conical intermediate sections 8.1, 8.2, 8.3, above the intermediate sections, a conical transition section 30 and, above the transition section, a conical head section 9 which has a circumferential, radially outwardly projecting flange 31 at the upper end 5. The above-mentioned sections 7, 8.1, 8.2, 8.3, 40 and the flange 31 directly adjoin one another. The outer diameter of the tubular body 2 increases gradually from the lower end 3 to the upper end of the head section 9. The inner diameter of the tubular body 2 also gradually increases substantially from the lower end 3 up to the upper end 5 of the tubular body 2.

The pipette tip 1 has no shoulder between the intermediate section and the head section.

The flange 31 has a downwardly projecting rib 32 at the lower side, which extends radially outward from the head portion 9.

The flattening 12 extends from the underside of the flange 31 in the axial direction of the tubular body 2 as far as the upper edge region of the transition section 30. This pipette tip 1 also has three flat flattenings 12. The regions 13 of the head section 9 adjoining the flattened sections each have, in cross section, a circular-arc-shaped contour which extends over the entire region between two adjacent flattened sections 12.

One or more pipette tips 1 according to fig. 6 to 10 may be provided in a holder for pipette tips. Here, the pipette tip is inserted into a bore of the holder and is supported on the edge of the bore with a rib 32 at the underside of the flange 31. According to fig. 10, the socket portion 21 is pushed into the pipette tip 1 only partially up to the uppermost guide ridge 25. Further below, pipette tip 1 has another guide ridge 25 and below it a sealing ridge 23. The socket is pushed until the sealing bead 23, so that the pipette tip 1 is clamped in alignment and sealing manner against the socket 21. The guide ridge 25 also facilitates sealing of the pipette tip 1 on the pocket 21.

The sealing bead 23 is at the same time a braking bead which brakes the introduction of the orifice into the pipette tip 1. The braking effect is determined by the slope at the upper edge and the rounding at the top of the sealing strip 23.

List of reference numerals

1. Pipette tip

2. Tubular body

3. Lower end part

4. Lower opening

5. Upper end part

6. Upper part opening

7. Beginning section

8. Middle section

9. Head section

10. Shoulder

11. Outer ring circumference

12. Flattening part

13. Adjacent region

14. Curved profile

15. Contour of a straight line

16. Edge of a container

17. Inner ring circumference

18. Widening part

19. Lead-in slope part

20. Mating region

21. Sleeve opening part

22. Sealing structure

23. Sealing ridge

24. Guide structure

25. Guide ridge

26. Conical braking area

27. Central region(s)

28. Identification

29. Character(s)

30. Transition section

31. Flange

32. Rib

Claims

1. A pipette tip made of plastic having an elongated tubular body (2) with a lower opening (4) at a lower end (3) for the passage of liquid and an upper opening (6) at an upper end (5) for clamping onto a spigot of a pipetting device (21), wherein beside the upper opening (6) on the inner circumference of the tubular body (2) there is a mating region (20) for the spigot (21), characterized in that beside the upper opening (6) on the outer circumference (11) of the tubular body (2) there is at least one flattened section (12) extending in the axial direction, the wall thickness of the tubular body (2) in the cross-section of the tubular body (2) in the flattened section (12) respectively adjoining one of two regions (13) of the tubular body (2) adjoining the flattened section (12) decreases from the flattened section (27) towards the central region (27) of the flattened section, and the cross-sectional profile (13) of the tubular body (2) has a smaller curvature (i) than the straight or curved region (15) of the tubular body (2).

2. The pipette tip according to claim 1, wherein the tubular body (2) has, in a cross section at the outer circumference (11), in a region (13) adjoining the flattened section (12), a circular-arc-shaped curved contour (14) and, in the flattened section, a rectilinear contour (15) or a circular-arc-shaped contour having a larger radius of curvature than the contour in the region (13) adjoining the flattened section (12).

3. The pipette tip according to claim 1 or 2, wherein the tubular body (2) has a straight profile and/or a curved profile (15) in the flattened section (12) in all cross sections of the at least one flattened section (12).

4. The pipette tip of any one of claims 1 to 3, wherein the at least one flattened portion (12) extends in an axial direction at least over a portion of the mating region (20).

5. The pipette tip according to any one of claims 1 to 4, wherein the at least one flattened portion (12) extends up to a distance from the upper end (5) of the tubular body (2).

6. The pipette tip according to any one of claims 1 to 5, wherein the at least one flattened portion (12) extends up to the upper end (5) of the tubular body (2).

7. The pipette tip according to any one of claims 1 to 6, wherein the at least one flattened portion (12) extends down to or beyond a shoulder (10) on an outer circumferential periphery (11) of the tubular body (2).

8. The pipette tip according to any of claims 1 to 7, wherein the tubular body (2) has a plurality, preferably three, flattenings (12) on the circumference.

9. The pipette tip according to any one of claims 1 to 8, wherein the flattened portions (12) are evenly distributed over the outer circumference (11) of the tubular body (2).

10. The pipette tip according to claim 8 or 9, wherein the flattened portion (12) generally occupies a larger portion of the outer circumference (11) of the tubular body (2) than the portion of the tubular body (2) generally occupied by the region (13) adjoining the flattened portion in the circumferential direction.

11. The pipette tip according to any one of claims 1 to 9, wherein, in a cross section of the tubular body (2), a plurality of flattenings having a rectilinear profile define an outer circumference (11) of the tubular body (2) in the form of a polygon, preferably a regular polygon.

12. The pipette tip according to any of claims 1 to 11, wherein the tubular body (2) has on an inner circumferential periphery (17) of the fitting region (20) at least one inwardly projecting circumferentially surrounding sealing structure (22) and/or at least one inwardly projecting circumferentially surrounding guide structure (24) or having a plurality of sections spaced apart from one another and/or at least one inwardly projecting circumferentially surrounding detent structure (26) or having a plurality of sections spaced apart from one another.

13. The pipette tip according to claim 12, wherein the tubular body (2) has a plurality of sealing structures (22) and/or guiding structures (24) and/or braking structures (30) on an inner circumference (17), which have an undulating profile in a longitudinal section of the tubular body (2).

14. The pipette tip according to any of claims 1 to 13, wherein the tubular body (2) has a widening (18) and/or a lead-in slope (19) at the upper opening (6).

15. The pipette tip according to any one of claims 1 to 14, which is made of at least one thermoplastic, preferably at least one polyolefin, preferably at least one polypropylene and/or ethylene.

16. The pipette tip of any one of claims 1 to 15, having one or more of the following features:

17. A pipette tip system comprising a plurality of pipette tips (1) according to any of claims 1 to 16, wherein pipette tips of different pipette tip types have differently configured flattenings (12) and/or have different markings on the flattenings (12).

18. A pipetting system comprising at least one pipette tip according to any one of claims 1 to 17 and comprising a single channel pipetting device with a single cuff portion (21) for sheathing one pipette tip (1) and/or a multi-channel pipetting device with multiple cuff portions (21) for simultaneously sheathing multiple pipette tips (1).